; (function () {
  outer: for (let i = 0; i < 10; i++){
    console.log('顶层循环');
    for (let j = 0; j < 10; j++){
      console.log('内层循环', i, j);
      if (i*j>30) {
        console.log('退出顶层循环');
        break outer
      }
    }
  }
})()
